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STD.X Time: 2 hrs VISAKHAPATNAM PREBOARD EXAMINATION (JANUARY 2024) CHEMISTRY (SCIENCE PAPER -2) TOTAL MARKS : 100 Question paper : 80 Answers to this Paper must be written on the paper provided separately. You will not be allowed to write during first 15 minutes. This time is to be spent in reading the question paper. The time given at the head of this Paper is the time allowed for writing the answers. ---------------------------------------------------------------------------------------------------------------Section A is compulsory. Attempt any four questions from Section B. The intended marks for questions or parts of questions are given in brackets [ ] SECTION A [40 MARKS] (Attempt all questions from this Section. Question 1 [15marks] Choose the correct answers to the questions from the given options. (Do not copy the question, write the correct answers only.) i) Which pair of elements listed below will not undergo covalent bond formation? (a) H and O (b) C and H (c) C and Cl (d) Na and Cl. ii) Two bases which are not Alkali. (a) Al(OH)3 and ZnO (b) Na2O and K2O ( c) NaOH and KOH (d) Ca(OH)2 and NH4OH. iii) A metal M forms an oxide having the formula M2O3. It belongs to third period. The atomic no. and valency of the metal is : (a) 12 and 3 (b) 5 and 3 ( c) 13 and 2 (d) 13 and 3. iv) The precipitate which is insoluble in HNO3 but soluble in NH4OH.: (a) Pb(OH)2 (b) PbCl2 ( c) AgCl (d) AgOH v) The number of molecules in 3.6g of H2O: (a) 1.2 x 1023 (b) 0.2 x 1023 (c ) 6 x 1023 (d) 12 x 1023 vi) Which of the following pairs of metals are extracted only by electrolysis? (a) Na and Pb (b) Ca and Cu (c ) Na and Ca (d) Ag and K vii) Name an alloy of Cu used in musical instruments. (a) Brass (b) Bronze (c) Duralumin (d) German silver. viii) Mr. Raj Kumar happen to explain the acidity of HCl using red rose petals. Which of the following will show the acidity? (a) Dry HCl gas (b) wet red rose petals (c) Dry HCl and dry Rose petals (d) All of the above. ix) In the manufacture of Sulphuric acid ,SO3 is absorbed in : (a) H2O (b) Conc.H2SO4 (c) Quartz (d) Oleum ix) A yellow precipitate obtained by the passage of H 2S through a solution of Lead nitrate is of: (a) PbCl2 (b) Pb(OH)2 (c) PbSO4 (d) PbS
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